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NetBSD 6.1.5 - man page for sort (netbsd section 1)

SORT(1) 			   BSD General Commands Manual				  SORT(1)

     sort -- sort or merge text files

     sort [-bcdfHilmnrSsu] [-k field1[,field2]] [-o output] [-R char] [-T dir] [-t char]
	  [file ...]

     The sort utility sorts text files by lines.  Comparisons are based on one or more sort keys
     extracted from each line of input, and are performed lexicographically.  By default, if keys
     are not given, sort regards each input line as a single field.

     The following options are available:

     -c 	 Check that the single input file is sorted.  If the file is not sorted, sort
		 produces the appropriate error messages and exits with code 1; otherwise, sort
		 returns 0.  sort -c produces no output.

     -H 	 Ignored for compatibility with earlier versions of sort.

     -m 	 Merge only; the input files are assumed to be pre-sorted.

     -o output	 The argument given is the name of an output file to be used instead of the stan-
		 dard output.  This file can be the same as one of the input files.

     -S 	 Don't use stable sort.  Default is to use stable sort.

     -s 	 Use stable sort, keeps records with equal keys in their original order.  This is
		 the default.  Provided for compatibility with other sort implementations only.

     -T dir	 Use dir as the directory for temporary files.	The default is the value speci-
		 fied in the environment variable TMPDIR or /tmp if TMPDIR is not defined.

     -u 	 Unique: suppress all but one in each set of lines having equal keys.  If used
		 with the -c option, check that there are no lines with duplicate keys.

     The following options override the default ordering rules.  When ordering options appear
     independent of key field specifications, the requested field ordering rules are applied
     globally to all sort keys.  When attached to a specific key (see -k), the ordering options
     override all global ordering options for that key.

     -d 	 Only blank space and alphanumeric characters are used in making comparisons.

     -f 	 Considers all lowercase characters that have uppercase equivalents to be the
		 same for purposes of comparison.

     -i 	 Ignore all non-printable characters.

     -l 	 Sort by the string length of the field, not by the field itself.

     -n 	 An initial numeric string, consisting of optional blank space, optional minus
		 sign, and zero or more digits (including decimal point) is sorted by arithmetic
		 value.  (The -n option no longer implies the -b option.)

     -r 	 Reverse the sense of comparisons.

     The treatment of field separators can be altered using these options:

     -b 	 Ignores leading blank space when determining the start and end of a restricted
		 sort key.  A -b option specified before the first -k option applies globally to
		 all -k options.  Otherwise, the -b option can be attached independently to each
		 field argument of the -k option (see below).  Note that the -b option has no
		 effect unless key fields are specified.

     -t char	 char is used as the field separator character.  The initial char is not consid-
		 ered to be part of a field when determining key offsets (see below).  Each
		 occurrence of char is significant (for example, ``charchar'' delimits an empty
		 field).  If -t is not specified, the default field separator is a sequence of
		 blank-space characters, and consecutive blank spaces do not delimit an empty
		 field; further, the initial blank space is considered part of a field when
		 determining key offsets.

     -R char	 char is used as the record separator character.  This should be used with dis-
		 cretion; -R <alphanumeric> usually produces undesirable results.  The default
		 record separator is newline.

     -k field1[,field2]
		 Designates the starting position, field1, and optional ending position, field2,
		 of a key field.  The -k option replaces the obsolescent options +pos1 and -pos2.

     The following operands are available:

     file	   The pathname of a file to be sorted, merged, or checked.  If no file operands
		   are specified, or if a file operand is -, the standard input is used.

     A field is defined as a minimal sequence of characters followed by a field separator or a
     newline character.  By default, the first blank space of a sequence of blank spaces acts as
     the field separator.  All blank spaces in a sequence of blank spaces are considered as part
     of the next field; for example, all blank spaces at the beginning of a line are considered
     to be part of the first field.

     Fields are specified by the -k field1[,field2] argument.  A missing field2 argument defaults
     to the end of a line.

     The arguments field1 and field2 have the form m.n and can be followed by one or more of the
     letters b, d, f, i, l, n, and r, which correspond to the options discussed above.	A field1
     position specified by m.n (m, n > 0) is interpreted as the nth character in the mth field.
     A missing .n in field1 means '.1', indicating the first character of the mth field; if the
     -b option is in effect, n is counted from the first non-blank character in the mth field;
     m.1b refers to the first non-blank character in the mth field.

     A field2 position specified by m.n is interpreted as the nth character (including separa-
     tors) of the mth field.  A missing .n indicates the last character of the mth field; m = 0
     designates the end of a line.  Thus the option -k v.x,w.y is synonymous with the obsolescent
     option +v-1.x-1-w-1.y; when y is omitted, -k v.x,w is synonymous with +v-1.x-1-w+1.0.  The
     obsolescent +pos1 -pos2 option is still supported, except for -w.0b, which has no -k equiva-

     If the following environment variable exists, it is used by sort.

     TMPDIR	      sort uses the contents of the TMPDIR environment variable as the path in
		      which to store temporary files.

     /tmp/sort.*	Default temporary files.
     outputNUMBER	Temporary file which is used for output if output already exists.  Once
			sorting is finished, this file replaces output (via link(2) and

     Sort exits with one of the following values:
     0	   Normal behavior.
     1	   On disorder (or non-uniqueness) with the -c option
     2	   An error occurred.

     comm(1), join(1), uniq(1), qsort(3), radixsort(3)

     A sort command appeared in Version 5 AT&T UNIX.  This sort implementation appeared in 4.4BSD
     and is used since NetBSD 1.6.

     Posix requires the locale's thousands separator be ignored in numbers.  It may be faster to
     sort very large files in pieces and then explicitly merge them.

     This sort has no limits on input line length (other than imposed by available memory) or any
     restrictions on bytes allowed within lines.

     To protect data sort -o calls link(2) and unlink(2), and thus fails on protected directo-

     Input files should be text files.	If file doesn't end with record separator (which is typi-
     cally newline), the sort utility silently supplies one.

     The current sort uses lexicographic radix sorting, which requires that sort keys be kept in
     memory (as opposed to previous versions which used quick and merge sorts and did not.)  Thus
     performance depends highly on efficient choice of sort keys, and the -b option and the
     field2 argument of the -k option should be used whenever possible.  Similarly, sort -k1f is
     equivalent to sort -f and may take twice as long.

BSD					December 18, 2010				      BSD

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